In an endothermic reaction products are <u>HIGHER </u>than reactants in potential energy and <u>LESS </u>stable.
Explanation:
Energy is input into the reaction in an endothermic reaction. This means the products are of a higher energy level than the reactants. Therefore the reaction increases Gibb's free energy and reduces entropy. Remember in thermodynamic stability involves an increase in entropy and a decrease in Gibbs free energy. Therefore the products are less stable than the reactants. This is why endothermic reactions do not occur spontaneously like exothermic reactions.
Answer:
b) 3.10
Explanation:
HF ⇄ H
+ + F
Using Henderson-Hasselbalch Equation:
pH = pKa + log [A-]/[HA].
Where;
pKa = Dissociation constant = -log Ka
Hence, pKa of HF = -log 7.2 x 10^-4 = 3.14266
[A-] = concentration of conjugate base after dissociation = moles of base/total volume
= 0.15 x 0.3/0.8
= 0.05625 M
[HA] = concentration of the acid = moles of acid/total volume
= 0.10 x 0.5/0.8
= 0.0625 M
Note: <em>Total volume = 500 + 300 = 800 mL = 0.8 dm3</em>
pH = 3.14266 + log [0.05625/0.0625]
= 3.14267 + (-0.04575749056)
= 3.09691250944
<em>From all the available options below:</em>
<em>a) 2.97
</em>
<em>b) 3.10
</em>
<em>c) 3.19
</em>
<em>d) 3.22
</em>
<em>e) 3.32</em>
The correct option is b.
Answer:
There is 27.6 mL of a 0.200 M HNO3 solution required
Explanation:
<u>Step 1: </u>The balanced equation is:
Na2CO3(aq)+2HNO3(aq)→2NaNO3(aq)+CO2(g)+H2O(l)
This means for 1 mole Na2CO3 consumed, there is consumed 2 mole of HNO3 and there is produced 2 moles of NaNO3, 1 mole of CO2 and 1 mole of H2O
<u>Step 2: </u>Calculating moles of Na2CO3
moles of Na2CO3 =volume of Na2CO3 * Molarity of Na2CO3
moles of Na2CO3 = 27.6 *10^-3 * 0.1 M = 0.00276 moles
<u>Step 3: </u>Calculating moles of HNO3
In the balanced equation, we can see that for 1 mole of Na2CO3 consumed, there are consumed 2 moles of HNO3.
So for 0.00276 moles consumed of Na2CO3, there are consumed 0.00552 moles of HNO3.
This means 0.00276 moles of the base Na2CO3 would react with 0.00552 moles of the acid HNO3
<u>Step 4: </u>Calculating the volume of HNO3
volume of HNO3 = moles of HNO3 / Molarity of HNO3
volume of HNO3 = 0.00552 moles / 0.200 M = 0.0276 L
0.0276 L = 27.6 ml
There is 27.6 mL of a 0.200 M HNO3 solution required
V(NaOH)=15 mL =0.015 L
C(NaOH)=0.1 mol/L
C(H₂SO₄)=0.05 mol/L
2NaOH + H₂SO₄ = Na₂SO₄ + 2H₂O
n(NaOH)=V(NaOH)C(NaOH)=2n(H₂SO₄)
n(H₂SO₄)=V(H₂SO₄)C(H₂SO₄)
V(NaOH)C(NaOH)=2V(H₂SO₄)C(H₂SO₄)
V(H₂SO₄)=V(NaOH)C(NaOH)/{2C(H₂SO₄)}
V(H₂SO₄)=0.015*0.1/{2*0.05}=0.015 L = 15 mL
HELP ME!!!
Project: Modeling potential and kinetic energy
Assignment Summary
For this assignment, you will develop a model that shows a roller coaster cart in four different positions on a track. You will then use this model to discuss the changes in potential and kinetic energy of the cart as it moves along the track.
Background Information
The two most common forms of energy are potential energy and kinetic energy. Potential energy is the stored energy an object has due to its position. Kinetic energy is the energy an object has due to its motion. An object’s kinetic energy changes with its motion, while its potential energy changes with its position, but the total energy stays the same. If potential energy increases, then kinetic energy decreases. If potential energy decreases, then kinetic energy increases.
Potential energy related to the height of an object is called gravitational potential energy. Gravitational potential energy is directly related to an object’s mass, the acceleration due to gravity, and an object’s height.
Materials
One poster board per student Drawing utensils
Assignment Instructions
Step 1: Prepare for the project.
a) Read the entire Student Guide before you begin this project.
b) If anything is unclear, be sure to ask your teacher for assistance before you begin.
c) Gather the materials you will need to complete this project.
Step 2: Create your poster.
a) On the poster board, draw a roller coaster track that starts with one large hill, then is followed by a valley and another, smaller hill.
b) Draw a cart in four positions on the track as outlined below.
i. Draw the first cart at the top of the first hill. Label it A.
ii. Draw the second cart going down the first hill into the valley. Label it B.
iii. Draw the third cart at the bottom of the valley. Assume that the height of the cart in this position is zero. Label it C.
iv. Draw the last cart at the top of the second, smaller hill. Label it D.
c) Make sure that your name is on the poster. Step 3: Type one to two paragraphs that describe the energy of the cart.
a) Type one to two paragraphs describing the changes in potential and kinetic energy of the cart. Be sure to discuss how the potential and kinetic energy of the cart changes at each of the four positions along the track, and explain why these changes occur.
b) Make sure your name is on the document.
c) Later, you will submit this document through the virtual classroom.
Step 4: Evaluate your project using this checklist.
If you can check each criterion below, you are ready to submit your project.
Did you draw a model of a roller coaster track with one large hill, a valley, and a smaller hill?
Did you draw a cart on the track in the four required positions A–D? Did you label the cart at each of the four positions?
Did you type a paragraph describing the changes in potential and kinetic energy of the cart at each of the four positions on the roller coaster track? Did you explain why the changes in potential and kinetic energy occur?
Step 5: Revise and submit your project.
a) If you were unable to check off all of the requirements on the checklist, go back and make sure that your project is complete.
b) When you have completed your project, submit your poster to your teacher for grading. Be sure that your name is on it.
c) Submit the typewritten document through the virtual classroom. Be sure that your name is on it.
Step 6: Clean up your work space.
a) Clean up your work space. Return any reusable materials to your teacher and throw away any trash.
b) Congratulations! You have completed your project.
Electric energy and sink
